IntelliJ IDEA 2016.2 Help

Reloading Classes

Introduction

You can reload classes changed during debugging without need to restart the entire application using the
HotSwap mechanism.

At the moment due to original limitations of Java SDK the HotSwapping
is possible ONLY if a method body is altered. In all other cases (like changing method or class signature),
the class reload is impossible and the corresponding error message appears.

Reloading changed classes

To reload changed classes

Do one of the following:

On the main menu, choose Run | Reload Changed Classes.

On the main menu, choose Build | Compile "class_name" to recompile an
altered class during debug.